Fix undefined link-time references for unit tests (sorry Phill I've just given
it what it needs, not elegant...)
Test SiR1-sum-F explicitly in unit tests as it's a tricky channel.
Use a more restrictive, but better behaved test for strings in channel names.

Fixes issue #151.
Merge branch 'feature/BK_issue_151' into develop
Bad logic broke IdChannel for detectors that don't have a fast / slow channel